Etching machine



Jan. 4, 1966 c. s. MARTZ 3,227,166

ETGHING MACHINE Filed Sept. 1P, 1962 2 Sheets-Sheet l INVEN/QOR CHARLES S. ARTZ 23 FIG. a.

BY Cerem,

A TTORN E YS ETCHING MACHINE Filed Sept. l?, 1962 FW 54* 56 T. i 6X6 70 24 il@ Q W x 311- S ,f WL N Mii; 64 52 /Z "f5 26 /2/ F|G.3 fs

INVENTOR CHARLES 5. MARTz BY MMM-(PMM A TTORNEY' 2 Sheets-Sheet 2 United States atent 3,227,166# p ETCHING lMACHlNE l Charles SJMartz, Aurora, Mo., assgnorfto'Tasop Limited, Aurora;` Mo., a corporation Filed Sept. 12,1962, Ser. No.V 223,169' 12 Claims. (Cl.13494) This application is a continuation-in-part of copending application- Serial No 25,921, tiled May'2, 1960, now-` Patent No.- 3,136,671'. e

This invention relates generally to improvements in an etching machine,- and'more particularly to improvements inan apparatus involving an etching bathin which 'a protective bath additive is utilized.

Various apparatus and methods, together with the attendant" advantages, pertaining 'to so-called powderlessl etching `are fully( discussed in the above `identified copending application.

An important objective is acliievedby'submerging th'e' plate tolbe etchedcornpletely'f in the etching bath,` and impartinga wobble motion to the workpiece, while bombardingthe lower, plate face with Haprofusion of bubbles passed upwardly'through vthe'bath so as to impin'ge and rollfupwardlycn the plate. Because'of the wobblem'o-4 tion,I the direction of bubble flow up along the lower face of the submerged plate is'constantly changing.

Thetprotective iilm `formed -by the bath additive is-in contact with-.the-plate at all times because the'` plate is submerged in the bath. The air bubbles remove tliebath" additive in the open areas to be etched. In addition, the iiow of the solution across the plate caused by the changing paths of the bubbles and by the-wobble'motionof the plate,.als causes removal.` of the protective bathu addi-j tive inthe open -areas to be t etched, yet completely'protects the side walls.

Another important fobjective is realizedcbythe use of the-prleviously ,described-wobble motion of the plate"dur. ing the etching action inthat thettanks size can be" only slightly largerthan the plate. Obviously, this desirable featurealfor'ds the use of a muchfsmaller bath and also. savesoor space, all of which contributesconsiderably" to economy of-manufactu're and operation.A

Still another important objectis realized by an improved. mechanism for actuating the' submerged" platewith av wobble motion that tilts the plate at a predetermined angle relative to the horizontal or bath level in alldirections-for yoptimum side wall uniformity.

An important object is provided by lthe provision' of a` rod holding the workpiece, a blleandsocket connection" mounting the rod, and a camtmeans` actuating the rodto impart the wobble motion tothe workpiece.

Other important'advantages are realized'in thattlie cam means includes a cam plate attached to and driven by a` drive shaft, the cam plate engaging andswingin'g one end. of the universallyl mounted rod to provide` the wobble motion withutrotating either the rod or workpiece:

Another" important object`- is "achieved by gthe: provision of means that interconnect theworkholder witha station# ary portion' of thetank assemblyfso 1 that the workliolder,` and `hence theworkpiece; is precluded fromlrota'tion yeti allowedv tov wobble."v

Yeti anotherimportant' objectris to J .provide ia 1 compact etching machine that is simple and durable inconstruc-A l tion,` economicalato manufacturacicient: in operation,

costs less to maintain, reduces-.bathI cost' becauselofA the longerl batli lifefobtained and because -oiiA Athesmaller bath size required, enables a reduction in-tanksize, and which savesiioor space,

The foregoingand `numerous otherobjectsand advantages of the invention will'more clearlyappear from the following detailed vdescription of `a preferred embodi- 3,227,166 Patented Jan. 4, 1966 ment," particularly when considered' in connection with tion ofthe` ball and socket connection and mountingof" the workholder. Referring'now by characters of reference Vtothe-drawlngs, and iirst to FIGS. 2 and 3, `it is seen that `the etching machineincludes a base generally indicatedat 10 which holds a tank referred to at 11. From FIG. 3, it is seen that the tank 11` hasl a bottom wall 12, opposed Vertical side walls 13, a verticalrear wall 14 and an upwardly and outwardly inclined front wall` 15'. A lid 16 for the tank 11 is hingedly mounted at 17'to the upper margin of rear wall14. Attached to the upper'surface of lid'16 isv a rearwardly extending arm 20.

Operatively interconnecting thev base 10 with the 1id"16r is a hydraulic ram 21 adapted to raise andlower thelid 1`6relative to the tank 11. More particularly,` the cylin" der 22 of ram 21 is pivotally connected by pin'23 to the baselwhile thecoacting piston24 is pivotally connectedA by pin 25 to the rearmostend of arm 20. It is seen from L FIG. 2 that as piston 24is retracted in cylinder 22'the lid 16V is swungiupwardly from its closed position illustrated infull-lin'es'to the raised position indicated byV broken lines. Of course, the ram 21 is allowed to adjust its angular position necessary to providethis result by its pivotalconnections 23iand 25 to the base 10 and arm 20. The piston24 is then extended to swing the lid 161to its closedposition,

Extending forwardly from the front tank wall 15is a panel assembly 26 on-which the-various control instru-` ments such as those indicated at 27 inFIGS. l and2 canl` be'mounted.

Thedrivemechanism is `mounted onV and carriedtby: the tank lid 16. For example, a casting 30`is securedV to" the top loflid 16,` the casting 30 including anupright'post" 31"'providing a `rotativebearing `mountingfor a verticall drive"'sliaft 32; A pulley 33 is drivingly connected to.'- theUpperend ofV drive shaft 32. Mountedon the casting 30 `is a drive motor 34 that operates through' a speed-re ducing unit torotate a coacting pulley 36;- Thepulleysv 33 and 36J are operatively'interconnected by a drive belt 37. As is best seen in FIGS; l and 2, the kdrive Imechanism is enclosed on the lid 16 by a housing 40:

Attached to the undersideof lid 16 anddisposed `about thetlower end of drive shaft 32 is a cylindrical member" 41^that constitutes a part of a wobble-imparting'mecha-l nism described in detail subsequently. Attached to the cylindrical member 41 are a plurality (a total offour in' the' embodimentdisclosed) ofregularly spaced; dependingstraps 42. These straps 42 taper downwardly and are* constructed to provide'a ball" socket formation indicated" at` 4.3 and clearly shown in FIG; 4. Specifically, theselowel" endsjof straps 42"'are provided with" rounded upv turned flanges 414;V Cooperating ^arcuate ilanges-45fare securedby fasteners 46 to the underside ofthe lower ends* of"straps42. These arcuate flanges'44 and 45 cooperate' to form the ballsocket43:`

Universally mountedin the ballsocket V43 is a ball 47. Carried byand'movable with the ball 47 is a rod-5).`v` The lower end 51-ofrod5ilis attached'to'a workholder 52'.'

The workholder 52 is substantially rectangular in configuration as isbest seen in FIG. 3 and closely approximates the internal dimensions of the-tank 11; As will be clear upon subsequent description of parts, the tank size may be only slightly larger than the workholder 52 because the workholder 52 is not rotated during etching, but on the contrary is moved with a wobble motion.

A plurality of triangular braces 53 are secured to the upper surface of the workholder 52 and are secured together at their upper edges by a circular ring 54.

Drivingly connected to the lower end of drive shaft 32 is a cam 55, the cam 55 being provided with an aperture 56 offset laterally from the drive shaft 32. The upper rod end 57 is disposed in cam aperture 56 and is carried by the cam 55 upon rotation of drive shaft 32.

In the preferred embodiment, it is seen that the ball 47 and cooperating socket 43 is aligned axially with the drive shaft 32. Because the upper rod end 57 is offset laterally from the drive shaft axis and is rotated in a circle by the cam 55 upon rotation of the drive shaft 32, the lower rod end 51 and hence the workholder 52 is moved with a wobble motion so that the workholder 52 is tilted at an angle to the horizontal in all directions.

A workpiece indicated at 60 is attached to the underside of the workholder 52 by any suitable and conventional means, the workpiece 60 being tilted with a wobble motion with the workholder 52. Preferably, the workpiece 60 is tilted at an approximate angle of eight (8) degrees in all directions for most effective etching action.

The tank 11 holds a quantity of etchant the level of which must be above the corners of the workholder 52 when the corners are in the high position as is indicated by level line 61 in FIG. 2. It will be noted that the workpiece 60 is maintained completely submerged in the etchant bath at all times during etching.

To preclude the workholder 52 and hence the workpiece 60 from rotating during the wobble motion imparted by rod t), a pair of resilient fingers 62 grip opposite sides of one of the braces 53 when the lid 16 is closed. The fingers 62 are attached to the underside of lid 16.

Located at the bottom of tank 11 and supported on the bottom wall 12 is an aeration assembly including a header 63 that operatively connects and communicates with a plurality of elongate, parallel air tubes 64 extending transversely of tank 11. Each of the air tubes 64 is provided with a plurality of small air holes 65 on its underside. A feed line 66 is connected to the header 63 and also connects to a centrifugal pump (not shown) by tubing 67. Another tubing 70 communicates the feed line 66 with an air gauge 71 on the control panel 26, the gauge 71 being used only to check back pressure. Enough air must be put into the system to force it out every hole 65 at the same velocity. To do this, more air is used than can escape out of the system. The back pressure gauge 71 records excess air pressure.

Air is forced through the air tubes 64 and is emitted through the air holes 65 in the form of ne bubbles that rise upwardly through the etching bath and impinge and roll upwardly on the workpiece 6). In addition to this etching action of the bubbles as explained later, the air emitted through air holes 65 keeps the bath agitated and thoroughly mixed.

As is usual in etching machines and methods of etching, temperature of the bath must be maintained within certain specified limits in order to obtain best results. Formed as a part of the bottom wall 12 are refrigeration coils 72 as is best seen in FIG. 2. Suitable insulation 73 is provided about such coils 72. Upon selective operation of the refrigeration coils 72, either manually or automatically by control means, the bath temperature can be maintained at a desired operating point.

It is thought that the operation and functional advantages of the machine and method have become fully apparent from the detailed description of parts, but for completeness of disclosure, such operation will be briefly described.

In making the particular powderless etching bath, the tank 11 is iilled with water to a preset water gauge and then the nitric acid is added. The water and acid go into solution. This mixture is cooled to about 75 degrees and then the bath additive is introduced. The air pump is turned on and the air emitted from air holes 65 rises upwardly through the bath to provide thorough agitation that mixes the oils, water and acid. Because the mixture is not a true emulsion, the oils will rise to the surextremely important that the bath must be agitated before the workpiece 60 is placed into the bath or else the face of the bath if the air is turned olf. Therefore, it is oil will cover the workpiece and attach itself so completely that the acid cannot etch the plate at all.

Assuming that the print on the workpiece 60 is properly exposed, developed and burnt-in, the first step is to paint out the large bare zinc areas with any lacquer preparation that will stand up under the acid and the oil in the powderless etching both. The space painting is not absolutely essential to etching and will have very little effect upon the actual etching process. Then, the dry plate is brushed thoroughly with a prepared mixture of nitric acid, water and a metal cleaning solution in order to remove scum. This de-scum solution is flushed oif of the plate and then the print is brushed or sponged with a pre-etch solution consisting of nitric acid and water. After pre-etching the plate, the plate is flushed with water prior to gumming. Then a few drops of a regular gum arabic solution is dropped on the wet plate and brushed over the entire surface, thus eliminating oxidation and keeping the plate from drying out while being attached to the workholder The air pump is started in order to cause agitation of the bath before the lid 16 is closed. The lid 16 is then closed, and the workpiece 60 is completely submerged in the etching bath. The drive means 34 is energized so as to rotate the drive shaft 32. As explained previously, upon rotation of the drive shaft 32, the cam 55 will act through the universally mounted ball 47 and rod 50 to impart a wobble motion to the workholder 52 and hence to the workpiece 60.

It is seen that etching action is achieved by submerging the workpiece 60 completely in the etching bath and imparting a wobble m-otion to the workpiece 60 while bombarding the lower plate face with a profusion of bubbles passed upwardly through the bath so as to impinge and roll upwardly on the plate. Because of the wobble motion, the direction of bubble ow up along the lower -face of the submerged plate is constantly changing.

Briefly stated, the drive mechanism actuates the submerged workpiece 60 with a wobble motion that tilts the workpiece at a predetermined angle, preferably eight (8) degrees, relative to the horizontal or bath level in all directions for optimum side wall uniformity.

The protective film formed by the bath additive is in Contact with the plate at all times because the plate is submerged in the bath. The air bubbles remove the bath additive in the open areas to be etched. In addition, the flow of the solution across the plate caused by the changing paths of the bubbles and by the wobble motion of the plate, also causes removal of the protective bath additive in the open areas to be etched, yet completely protects the side walls. For example, the air bubbles remove the oil in the open areas to be etched, allowing the acid to act, but as any bubble moves along the plate, the bath following the bubbles again covers the plate and the protective oil or bath additive again provides side wall protection.

With the workpiece 60 tilted there is less action on the side opposite to the direction of bubble flow. The greater side wall protection is formed on the high side of the image, and because of the wobble motion of the workpiece 60 all sides of all images are put on the high side and hence the side walls are evenly protected. This produces better protection and again aids in producing shoulders or side walls with less porosity. When porostribute t considerablytoiH economy` of 1, `rnanufacture aand:

operation.

Althougntthe.inventionhas been.decentiedA by` making.

detailed reference to a single preferred embodiment, such detail is to be.understood pinan,.,instructive, rather than in any restrictivesensemany-variants being possible within the scope of the claims herennto appended.

-AI claim as my invention; 1.` In an etching machine (Va) a vtank-holding etchant,. (fb)means-holdingf-.a workpiece,submergedl in said etchant, t (c) meansreleasing .aia bubbles in saidaetchantbelow 4the workpiecw t (d.) .meansimaartinga,wcbhlamctcntcthe workpiece to tilt the workpiece all` directions at an angle to the horizontal..` slthat'l'the'idirection of bubble ilow up along the lowerlfacetzof-the submerged .workpiece is constantly changing, a i (e) means precluding rotationof said workpiece during ine;

(a) atan, p oldingetchant,

(b) means'including a ball and socket connection hold ing a workpiece submerged in said etchant,

(c) means releasing air bubbles in said etchant below the workpiece, and

(d) cam means imparting a wobble motion to the workpiece through the ball and socket connection so that the direction of bubble ow up along the lower face of the submerged workpiece is constantly changing.

3. In an etching machine:

(a) a tank holdingetchant,

(b) a rod holding a workpiece submerged in said etchant,

(c) a ball and socket connection mounting said rod,

(d) means releasing air bubbles in said etchant below the workpiece, and

(e) cam means actuating said rod to impart a wobble motion to the workpiece through the ball and socket connection so that the direction of bubble ow up along the lower face of the submerged workpiece is constantly changing.

4. In an etching machine:

(a) a tank holding etchant,

(b) a rod holding a workpiece submerged in said etchant,

(c) a ball and socket connection mounting said rod,

(d) means releasing air bubbles in said etchant below the workpiece,

(e) a drive shaft,

(f) a cam plate attached to and rotated by said drive shaft, the cam plate being operatively connected to said rod to swing the rod and hence impart a wobble motion to the workpiece so as to tilt the workpiece at an angle to the horizontal in al1 directions so that the direction of bubble flow up along the lower face of the submerged workpiece is constantly changing.

5, In an etching machine:

(a) a tank holding etchant,

(b) a rod having one end operatively attached to a workpiece and holding said workpiece submerged in said etchant,

(c) a ball and socket connection mounting said rod,

6 (d)v means ,releasing air ilblubbles rin saidetchaut below the workpiece, (e) adrivo shaft, (f) acam plate attached, to. and, rotatedftby saidzfdrive Vshaft, the, cam ,plate :being providedwithf an opening, an

.'(g). said `rodxfhavingits `opposite end received loosely in` said yopening yet connected .to the cam plate so that the plate swings the rod and hence imparts a wobble motion to the workpiecethroughlthe ball 4,and socket connection so that `the;.direction,offbubble ilow up along the tlower t face .of `the ,-submergedgworkpiece is constantly changing.

6. `In anetchng machine:

(a) ,a tankholding etchant,l

(b) a rod,

(c)-- a ball. and socket mountinglsaid rod-between v,its ends, a workholder attached to oneend `of said rod and holdinga workpiece submerged in ,saidtetchan (d) means ,releasing airfibubbles in saidetehant below the workpiece,A

(e) a drive shaft,

(f) a cam plate attached toand rotated by said d rive shaft, said cam plate being `provided with` an` opening,

(g) said rod having itsoppositeend receivedloosely in said Lopening yet operatively connected to the cam plate so `that the plateswings the rod and hence imparts a woble motionto the workholder and hence tothe workpiece through `the ball and socket connectionso .as totiltthe workpiecey at an angle to the horizontal in.f all directions `sohthat` the direction of bubble flow up along the lower face of ,the submerged workpiece is constantly changing, and

(h) means engaging said workholder to preclude rotation of said workpiece during said wobble motion.

7. In an etching machine:

(a) a tank holding etchant,

(b) a rod holding a workpiece submerged in said etchant,

(c) means universally mounting said rod between its ends,

(d) means releasing bubbles in said etchant below said workpiece, and

(e) means swinging said rod about its mounting to impart a wobble motion to the workpiece so that the direction of bubble flow up along the lower face of the submerged workpiece is constantly changing.

8. In an etching machine:

(a) I a tank holding etchant,

(b) a rod holding a workpiece submerged in said etchant,

(c) a ball and socket connection universally mounting said rod between its ends,

(d) means releasing bubbles in said etchant below said workpiece,

(e) a drive shaft, and

(f) a cam plate attached to and rotated by said drive shaft, the cam plate being operatively connected to said rod to swing the rod and hence impart a wobble motion to the workpiece through the ball and socket connection so that the direction of bubble tlow up along the lower face of the submerged workpiece is constantly changing.

9. In an etching machine:

(a) a tank holding etchant,

(b) a rod,

(c) a ball and socket universally mounting said rod between its ends,

(d) a workholder for a workpiece attached to one end of said rod and submerged in said etchant,

(e) means releasing bubbles in Said etchant below the workpiece,

(f) a drive shaft,

(g) a cam plate attached to and rotated by said drive shaft, the cam plate provided with an opening, and

' (h) the opposite end of said rod being received loosely in said opening yet connected to the cam plate so that the plate swings the rod and hence imparts a wobble motion to the workholder and workpiece through the ball and socket connection to tilt the workpiece at an angle to the horizontal at all directions so that the direction of bubble ow up along the upper face of the submerged workpiece is constantly changing.

10. In an etching machine:

(a) a tank holding etchant,

(b) means including a socket,

(c) a ball loosely mounted in said socket,

(d) a workholder adapted to hold a workpiece,

(e) means attaching said workholder to said ball for movement therewith and holding said workpiece submerged in said etchant,

(f) means releasing bubbles in said etchant below said workpiece, and

(g) means moving said ball in said socket to impart a wobble motion to the workpiece so that the direction of bubble tlow up along the lower face of the submerged workpiece is constantly changing.

11. In an etching machine:

(a) a tank holding etchant,

(b) means including a socket,

(c) a ball loosely mounted in said socket,

(d) a workholder adapted to hold a workpiece,

(e) a rod having one portion attaching said workholder to said ball for movement therewith and holding said workpiece submerged in said etchant,

(f) means releasing bubbles in said etchant below said workpiece,

(g) a drive shaft,

8 (h) a cam plate attached to and rotated by said drive shaft, and (i) said rod having another portion operatively connected to said cam plate so as to swing the rod and hence impart a wobble motion to the workpiece so that the direction of bubble flow up along the lower face of the submerged workpiece is constantly changing. 12. `The combination and arrangement of elements as 10 recited in claim 11, but further characterized by the provision of means engaging said workholder to preclude rotation of said workpiece during said wobble motion.

References Cited. bythe Examiner UNITED STATES PATENTS 1,016,487 2/1912 Freer 134-94 1,254,751 1/1918 Wendelgass 134-164 2,059,264 11/1936 Miller 68-153 X 2,439,262 4/ 1948 Nalbach 15-22 X 2,776,512 1/1957 Guenst 134-161 2,925,332 2/1960. Standley 156-14 2,999,013 9/1961 Meth 156-6 3,136,323 6/1964 Martz 134-94 FOREIGN PATENTS 566,913 1/ 1945 Great Britain. 591,694. v4/1959 Italy.

30 CHARLES A. WILLMUTH, Primary Examiner.

JACOB H. STEINBERG, GEORGE I. NORTH,

Examiners. 

7. IN AN ETCHING MACHINE; (A) A TANK HOLDING ETCHANT, (B) A ROD HOLDING A WORKPIECE SUBMERGED IN SAID ETCHANT, (C) MEANS UNIVERSALLY MOUNTING SAID ROD BETWEEN ITS ENDS, (D) MEANS RELEASING BUBBLES IN SAID ETCHANT BELOW SAID WORKPIECE, AND (E) MEANS SWINGING SAID ROD ABOUT ITS MOUNTING TO IMPART A WOBBLE MOTION TO THE WORKPIECE SO THAT THE DIRECTION OF BUBBLE FLOW UP ALONG THE LOWER FACE OF THE SUBMERGED WORKPIECE IS CONSTANTLY CHANGING. 